Grand Caravan V6-3.8L (2009)
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computer logic that remembers the settings of the controls when the ignition is turned off and retains those settings after a restart. If the system is
off when the ignition is turned off it will be off when the engine is restarted, etc.
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computer logic that provides variable air recirculation under high temperature and humidity conditions. Because recirculation is generally
accompanied by increased fan noise, the proportion of recirculated to outside air gradually approaches full recirculation over a broad temperature
range.
The front A/C-heater control utilizes integrated circuitry and information carried on the Controller Area Network (CAN) IHS bus to monitor many
sensors and switch inputs throughout the vehicle. In response to those inputs, the internal circuitry and programming of the A/C-heater control allows it
to control the electronic functions and features of the ATC heating-A/C system.
The inputs received by the A/C-heater control of the ATC heating-A/C system are as follows:
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Refrigerant Pressure
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Evaporator Temperature
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Engine Coolant Temperature
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Ambient Air Temperature
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Infrared Temperature Sensor
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Vehicle Speed
The messages broadcasted by the A/C-heater control of the ATC heating-A/C system are as follows:
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A/C Request
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A/C Select
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Rear Window Defogger (EBL) Request
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Heated Front Seat Requests
The front A/C-heater control is diagnosed using a scan tool See: Powertrain Management/Computers and Control Systems/Testing and
Inspection/Diagnostic Trouble Code Tests and Associated Procedures.
Prior to replacing an A/C-heater control, check for any Diagnostic Trouble Codes (DTCs) related to the heating-A/C systems and run the calibration
procedure to verify that the concern is not a system issue See: Testing and Inspection/Component Tests and General Diagnostics/HVAC System Test.
The front A/C-heater control cannot be repaired and must be replaced if inoperative or damaged.
REAR CONTROL PANEL
The rear A/C-heater control (1) is located in the rear overhead console and allows intermediate seat passengers to adjust rear air distribution, temperature
and blower motor speed when the rear heating-A/C system primary on/off control in the front A/C-heater control in the instrument panel is set to the on
position and the rear heater-A/C controls are NOT locked out by the driver and front seat passenger.
The rear A/C-heater control contains:
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a rotary control knob for fan speed selection and turning the rear heating-A/C system off or to Auto mode (2).
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a rotary control knob for temperature control of the rear discharged air (3).
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a rotary control knob for mode control of the rear discharged air (4).
The rear A/C-heater control is a slave potentiometer to the front A/C-heater control. See Rear A/C-Heater Control for more information.
